Historically, cosmetic compacts have been small, flat cases for containing and transporting cosmetic face powder, a powder puff for applying the cosmetic, and a mirror. Typically, compacts were hand sized or smaller cases that could be easily carried in a purse or pocket. Many of these face powders were mineral powders such as talc, often containing mineral pigments. Such mineral powders are typically insensitive to air, containing no components that discolor, decompose, or degrade when exposed to air and containing no volatile materials that could evaporate and damage the consistency of the product. The compacts for such cosmetics were usually flat hinged boxes of various shapes including round, square, oval, or rectangle, consisting of a cover and a base, and had a simple clip holding them closed. While such containers sometimes had a thin paper or plastic seal to prevent the cosmetic from scattering during shipping, this seal was removed and discarded by the consumer before using the cosmetic.
Advances in cosmetic technology and evolutions in packaging have led to the packaging of other types of makeup including eye shadow, lip gloss, rouges, concealers, and new varieties of face powders in small flat containers, some with and some without the associated applicators, and with or without mirrors. All of these containers have been referred to widely as compacts, and many share the same hinged-box construction of the earlier compacts. For the purposes of this patent application, the terms compact and cosmetic case will be used interchangeably to refer to such containers for cosmetics, with or without associated applicators, and with or without a mirror.
Compacts have many advantages, being easy to open and use, convenient to carry, and easy to store and pack. Many of the new cosmetics now being stored and transported in such containers, however, are more sensitive to oxygen, humidity, or air than mineral powders, and cosmetics stored in such containers frequently degrade. Many useful pigments discolor or decompose when exposed to air, and carriers for such pigments frequently contain volatile or air sensitive components. The previous hinged box form of compact is poorly suited for cosmetics containing volatile or air sensitive components. It is desirable, therefore, to provide a compact that retains the advantages of ease of opening and use, convenience of carrying, and ease of storage and packing, while also maintaining a reusable airtight seal to preserve the cosmetics before and between uses.
Several attempts have been made to provide an airtight function on a compact, typically by adding additional cover elements inside the compact. In general, providing an airtight function to a container requires either machining the base and the cover of the container from rigid materials to such close tolerances that the fit between the rigid materials leaves no airgaps, or utilizing flexible or elastomeric materials as seals which can be deformed under pressure to fill any openings between the base and the cover. In some designs, a separate inside container is provided, consisting of a cover and a base containing the cosmetic, the inside container fitting into the base of the compact and providing an airtight seal around the cosmetic. In use, the consumer must open first the cover of the compact and then the cover of the inside container to access the cosmetic, and close first the container cover and then the compact cover to store. To maintain the seal on the inside container, the compact lid is provided with either a thread or bayonet-like cam design which locks onto the compact base and applies pressure to the cover of the inside container.
On other airtight compacts, the airtight function is achieved by providing an internal smaller cover that interacts with the base of the compact. In some examples, a flat gasket is pressed between the internal cover and the base to provide an airtight seal. Other examples provide a peripheral gasket such as an O-ring that interacts with a matching element on the base. Still other examples act by pressing a lip molded underneath the internal cover against the base. Similar to examples having a separate inside container, the internal cover is kept in place by the compact cover pressing down on the inside lid and locking on the base by either a thread or a bayonet like cam design. Like compacts with a separate inside container, compacts with internal covers require opening both the compact cover and an interior cover before the cosmetic container can be accessed, and closure of both an interior cover and the compact cover are required for airtight storage.